System for fabricating structural members

ABSTRACT

A system for making joists including the steps of forming a zigzag-shaped web midsection and opposite ends adapted to fit together to provide a continuous joist web of predetermined depth and length, forming a bottom chord to extend between the opposite ends of the bottom of the web, assembling said web and bottom chord, forming a top chord, mounting shoes and plugs on the top chord, aligning the top chord with the assembled web and bottom chord, tacking an end of the web and the top chord which are in registry to maintain the alignment, and completing connection of the top chord and web to form a finished joist.

United States Patent Gooder [451 Jan. 25, 1972 Robert M. Gooder, 2537 Country Club Drive, Olympia Fields, 111. 60461 [22] Filed: Feb. 11, 1970 [21] App1.No.: 10,560

[72] Inventor:

[52] US. Cl. ..29/l55 R, 29/200 B [51] Int. Cl. ..B23p 17/00, 823p 19/00 [58] Field of Search ..29/l55 R, 200 B, 155 C, 429.

[56] References Cited UNITED STATES PATENTS 1,967,827 7/1934 Leake ..29/155R Leake ..29/l55 R Moore et al. ..29/155 R X Primary Examiner-Thomas H. Eager Attorney-E. Manning Giles, .1. Patrick Cagney and Peter S. Lucyshyn 5 7 ABSTRACT A system for making joists including the steps of forming a zigzag-shaped web midsection and opposite ends adapted to fit together to provide a continuous joist web of predetermined depth and length, forming a bottom chord to extend between the opposite ends of the bottom of the web, assembling said web and bottom chord, forming a top chord, mounting shoes and plugs on the top chord, aligning the top chord with the assembled web and bottom chord, tacking an end of the web and the top chord which are in registry to maintain the alignment, and completing connection of the top chord and web to form a finished joist.

13 Claims, 14 Drawing Figures PATENTED JANZS I972 3336602;

sum 1 nr 7 PATENTED JAN251972 SHEET 2 BF 7 PATENTEU JANZSISTZ 31636304 snmanw alssasm PATENTED JAN2519Y2 SHEET M 0F 7 SYSTEM FOR FABRICATING STRUCTURAL MEMBERS BRIEF SUMMARY OF THE INVENTION The present invention is in certain apparatus and a process for fabricating structural members, one example of which is joists. Some types of joists have been standardized as to depth, but are custom manufactured as to length. The wide range of length and depth combinations for structural members, for example such as those used in the building trade, does not pennit stock piling. Furthermore, the demand for any size is unpredictable and time to deliver is usually short. The structural members may be sold on a per pound basis so that a savings in labor as well as material, while meeting strength standards, is desirable. Thus, there has been a search in the art for methods of making structural members which is versatile, allowing different sizes to be manufactured, yet not too cumbersome so as to permit changing from one size to another. The prior art has not met the industry needs. The prior art methods involve too many manual or handling steps, too much storage of equipment not in use, and too much time and effort to adapt equipment to handle a change in size of manufactured structural member.

Accordingly, it is an object of the present invention to provide an improved method and certain apparatus for fabricating a structural member by effecting a continuous flow of materials through a set of integrated steps starting with raw stock and finishing with a structural member of made-to-order specifications, including size, strength and configuration.

It is a more detailed object of the present invention in accordance with the above to provide a method and certain apparatus for fabricating structural members, for example joists of the type described, so that alterations in specifications, for example strength, weight, mountings and the like, can be easily made to meet particular needs of a job.

It is yet another detailed object of the present invention in accordance with the above to provide a method and certain apparatus for fabricating a structural member that includes a set of steps which permit easy monitoring of the quality of work during the fabricating procedure and permit manufacture of not only standard size structural members but all sizes having the general configuration hereinafter described, yet increase the speed with which structural members can be manufactured.

It is an overall object of the present invention to provide a method and certain apparatus for fabricating made-to-order structural members in accordance with the above which permits economical manufacture of structural members and which is easy to practice.

Other objects and advantages of the present invention" will become apparent from a reading of the following detailed description and upon reference to the drawings in which:

FIG. 1 is a perspective of an exemplary structural member fabricated in accordance with the process of the present invention;

FIG. 2 is an end elevation of the structural member of FIG. 1;

FIG. 3 is a flow diagram, identifying fabricating steps by blocks, showing an exemplary system for practicing the present invention;

FIG. 4 is a top plan of an exemplary machine adapted to perform the step of Station B of FIG. 3;

FIG. 5 is a front elevation of an exemplary machine adapted to perform the step of Station D of FIG. 3;

FIG. 6 is an elevation as viewed from 6-6 in FIG. 5;

FIG. 7 is a side elevation, enlarged, of the exemplary machine shown in FIG. 5;

FIG. 8 is an elevation as viewed from 8-8 in FIG. 7;

FIG. 9 is a top plan of an exemplary machine adapted to perform the step of Station F of FIG. 3;

FIG. 10 is an elevation as viewed from l0- 10 in FIG. 9;

FIG. 11 is a top plan of an exemplary machine adapted to perform the step of Station G in FIG. 3;

FIG. 12 is an elevation as viewed from l2-12 in FIG. ll;

FIG. 13 is an elevation in partial section of a clamping mechanism in the exemplary machine of FIGS. 11 and 12 taken on line 13-13 of FIG. 12;

FIG. 14 is a schematic of a control circuit in the machine of FIG. 11. unpredictable Turning to the drawings and FIGS. I and 2 in particular, thereshown is an exemplary structural member, a joist I0 having a longitudinally extending intermediate member or section, herein shown as a web 11, and respective longitudinally extending side members or sections, herein shown as a bottom chord l2 and a top chord 14. The web is exemplarily shown as being round steel stock formed into a zigzag or serpentine shape with a midsection l5, respective opposite ends 16, 18 and a plurality of lower and upper stress or load points 19 and 20, respectively, one being aligned along the lower periphery of the web and the other being aligned along the upper periphery of the web. The web portion between two upper stress or load points is defined as a panel, one such panel being identified by a reference character 21. In the exemplary practice of the invention, the distance between adjacent stress points has been set at a predetermined constant value for the different depth sizes of joists, that distance being 2 feet. Other distances may be used, however, for one practical instance of the use of the invention 2 feet has been found desirable.

The bottom chord 12 is exemplarily shown as comprised of two round steel bars 22, 24 connected so as to sandwich between them lower stress or load points 19 of the web. The lower chord extends the length of the joist, connecting all of the web lower load points. The top chord I4 is exemplarily shown as comprised of two steel angles 25, 26 connected on opposite sides of the upper stress or load points 20, sandwiching the web therebetween. The top chord provides a surface suitable for receiving a structural load, for example slabs of concrete fonning a roof, floor or road surface or other joists, spaced and extending transversely.

To facilitate installation of the joist 10 at a job site, it may be desirable to provide shoes at opposite ends of the top chord 14. Four such shoes 28, 29, 30 and 31 are exemplarily shown.

Additional strengthening of the joist can be effected at the ends by installing respective struts 32, 34, intersecting the top chord at the next panel load point. Because the material used in making the structural member is steel, welding is used as the exemplary fastening means to connect the respective components together. It is appreciated by those skilled in the art that if other materials are used then other suitable fastening means can be utilized.

As will be understood by those skilled in the art certain characteristics of several types of joists have been specified. For example, see the Steel Joist Institute, Standard Specifications and Load Tables, 1969 Edition (printed yearly). The standard joists are available in certain nominal depth sizes, reference character 35 in FIG. 2 represents the depth dimension of a joist. The sizes start at 8 inches and go up to 24 inches, being available in two inch increments between these two sizes. The present invention has been used to manufacture steel joists of a depth of 28 inches, however, that is not considered to be an upper limit on the depth size which can be made. Within each depth size, there are designations to identify load carrying ability of different capacity joists. There are various ways to change the load carrying capacity of a joist. One way is to increase the size of the stock material from which the joist is manufactured, such as the size of the stock from which the web, bottom chord and top chord are fabricated. The present invention facilitates use of another practice for increasing the load canying ability of the joist. That practice uses plugs 36 located between the respective top chord angles 25, 26 as a part of predetermined ones of the panels 21, preferably panels which are in the midsection of the joist.

The length of the joist, represented by reference character 38 in FIG. 1, is made to order for the particular job. As will be explained subsequently, the present method permits the fabricator to guarantee that the joist will meet the length specification to within one-quarter of an inch, which for a foot span is to within about 0.06 percent. Joist can be made accurately, yet the method is sufficiently versatile to allow manufacture of joist within the aforementioned wide range of sizes.

A particular type of joist is selected as exemplary in order to describe the best mode contemplated of carrying out the present invention. It is understood, however, that other types of structural members having longitudinally extending sections along opposite sides and an intermediate section or 1 member spanning therebetween, all of which must be brought into registry and connected, can also be fabricated by using the present invention.

Turning now to FIG. 3, thereshown is a flow sheet representative of a system 43 for practicing the steps of the present structural member fabricating method. Starting materials for the structural member are received at Stations A, C, and E. In the exemplary practice of the method, the web midsection and ends are formed at Station A using round bar stock from a supply 40. For effectuating the zigzag form of the web, a zigzag web bender of the type manufactured by National Bending Machinery Corp., Jamestown, Pa., may be used. The forming machine at Station A fabricates both the midsection l5 and the opposite ends 16, 18 of the web.

In order to provide a web length which is correct for the length of joist that is being manufactured, a Station B is provided for shaping and cutting the web ends. An exemplary machine for performing this step is shown in FIG. 4. A web end 16, has been formed into a zigzag shape with a predetermined depth, that is distance between upper and lower stress or load points, corresponding to one of the standard joist depth sizes. The web ends are preformed in a stock size for the particular joist depth and preformed in a stock size for the particular joist depth and are adapted to be precisely fitted to the job-order joist being fabricated.

To provide such a stock size that can be finally fitted, the web end 16 is provided with an extension 46 having a length sufficient to extend out to a second, upper stress or load point, as viewed in FIG. 4, to the right beyond the lower stress or load point identified as 19a. The aforementioned upper stress point of the web is connected, after assembly is completed, to the top chord angles in proximity with the joist end. In order to tailor the web end to fit the joist length being fabricated, the extension is bent back at the bottom stress point 19a. As described subsequently, the web end extension 46 is bent so that when the respective web opposite ends 16, 18 and midsection 15 are combined the web is of the correct length for the particular joist. Each web end can be shortened a predetermined longitudinal distance depending upon the length of the joist being fabricated. Though in one practical instance the panel size of 2 feet is selected as uniform for all depth sizes of joist, the length of extension 46 for the maximum length joist is varied from 3 feet 9% inches for joist depths of 26 and 28 inches, to 2 feet 8 /a inches for joist depths of l2 inches.

To shape the web end to the desired form, it is first laid on a generally horizontal bed 48 and a side support rack 49 of the machine 45. It is then bent by a pivotable shaping arm 50 60 swinging across the bed 48 and acting against a positionable bulkhead 51. The bulkhead 51 is adjustable so that the machine can handle webs of different depths. To this end, a pair of nuts 52, 54 are provided on opposite ends of the bulkhead and a pair of threaded shafts 55, 56 carry the nuts 52, 54. 5

The threaded shafts are rotatably supported and can be turned by operation of a handcrank 58. The handcrank 58 is an integral part of shaft 56, and a chain and sprocket coupling 59 is provided at the rear of the machine to transmit drive from shaft 56 to shaft 55. Thus when crank 58 is turned, threaded 70 shafts and 56 turn in unison and transmit movement to the bulkhead 51 through the threaded nuts 52, 54.

To shape the web extension 46 to the correct angle and prepare it for a subsequent operation to cutoff the excess, the

pivotable arm 50 is provided with an adjustable jaw 60 slidable 75 longitudinally of the arm 50 in a slot 61 and held in position by a pair of bolts 62, 64. A lower bending block 65 is provided on the arm 50 to act adjacent the lower load point 19a and form a suitable bend of the web end in that regions. To provide a brace against which the extension 46 is bent, an anchoring block 66 is provided on the opposite side of the lower load point 19a. It holds the portion of the web in position that is not being bent. As exemplarily shown, the inclination of the anchoring block 66 can be adjusted by a set screw 68 to permit bending of web ends having various size panels.

To eflectuate pivoting of the shaping arm 50, a pair of pneumatic cylinders 69, 70 are mounted on respective horizontally extending outrigger anns 71, 72. One end of cylinder 69 is pivotably supported on ann 71 by suitable means, for example by a pintle 74, while an extensible piston portion of the cylinder 69 is connected to shaping arm 50 by suitable means, for example a pin 75. To provide supplementary power for moving arm 50, the cylinder 70 has one end anchored to arm 72, for example by a pintle 76 and an extensible arm of cylinder 70 connected to shaping arm 50 via a pivotable coupling, for example a pin 78.

As shown in phantom in FIG. 4, the arm 50 is swung around by actuation of cylinders 69, 70 to act against web end extension 46. For facilitating bending of the web end 16, the bulkhead 51 is supported a predetermined distanceabove the bed 48 so as to permit the arm 50 to swing under the bulkhead 51 and press the extension 46 against the latter. The jaw 60 engages the extension 46 and bends the latter forming the angle to load point 19a so that the extension 46 intersects a line 77, coextensive with the web top load points, at a predetermined location as calculated for the particular length of joist being manufactured. Subsequent to bending of the extension 46 a cutting operation is used to cut off the excess of web end material which would be a portion of the material bent into a straight form coextensive with line 77 and extending along the face of bulkhead 51. To facilitate attachment of the web end to the top chord, a longitudinal section 79 of the just described bent extension 46 may be left during the cutting operation.

The next step in the method, as represented by Station D in FIG. 3, is to assemble the respective web ends 16, 18 with the web midsection 15 and the bottom chord round bars 22, 24. In the present instance, the bottom chord is comprised of round steel bars, for example, 1% to 74 inch in diameter, though, of course, other suitable cross section shapes can be used. The round bars are received at a Station D from a Station C which cuts the bars to the correct length for the particular length of joist being fabricated. The lower chord length is equal to the distance between opposite ones, of the outer most, web lower load points. The round bars 22, 24 are placed on opposite faces of the web, as can be best seen in FIG. 7, and then suitable means are used to fasten the bars to the web, for example, by welding.

Turning now to FIGS. 5, 6, 7 and 8 which show an exempla- 5 'ry machine for carrying out the assembling of the web ends,

midsection and bottom chord (Station D), as best shown in FIGS. 5 and 7 the webs 11 are stored on overhead racks above the work area where the lower chord round bars are connected to the web lower load points. For that purpose a plurality of arms 80 of generally channeled cross section are provided having respective upstanding ribs 81 adapted to fit into the angle formed at the web upper load points 20.

In the exemplary procedure the bottom chord round bars 22, 24 are power fed to Station D by a suitable over-under belt drive, the bars being conveyed the length of the machine and then permitted to slide off into a storage bin 82 carried on upright frame posts 83. The over-under drive includes a plurality of upper rollers 84 positioned along the length of the machine and a plurality of lower rollers 85 also positioned the length of the machine, the rollers being staggered on opposite sides of an imaginary centerline. As best shown by dotted lines in FIG. 5, an upper portion 86a of a generally horizontal belt 86 is weaved over and under the set of staggered rollers 84, 85 so that drive is transmitted to the upper rollers 84 by the belt portion 86a. In this manner, the belt 86 does not come into contact with the bars, these being carried on the upper rollers 84, while drive is transmitted to the upper rollers over the full length of the machine. Drive can be applied to the belt 86 in any suitable manner, for example, an end roller 88 may be connected to a suitable source of rotative power, such as a motor. As can be observed in FIG. 7, the upper rollers 84 are wider than the lower rollers 85, the latter needing only to support the belt drive. The upper rollers 84 are rotatably supported at their opposite ends, for example by respective bearing supports 87, 89. A forward end 84a of the rollers 84 extends above the front support 89, so as to allow the bars 22 or 24 to be easily slid off into the bin 82.

In the exemplary practice of the method, the machine at Station D is arranged to clamp the respective chord bars 22, 24 in intimate contact with the web at the lower load points 19 of the latter. To this end, a platform is defined by locating it longitudinally spaced positions along the machine a plurality of fastening assemblies 90 adapted to engage the web at its lower load points 19.

Describing the web supporting and clamping assembly in further detail, the web 11 is held in a generally upright position leaning back against a rear wall 92, and is supported on a set of extending, inverted channels 94, one such channel being provided with each shelf assembly. A backstop 95 for engaging the lower chord is provided and includes respective prongs disposed on opposite sides of the inverted channel 94. The latter arrangement permits an aligning tang 96 to swing down against the channel 94 to press the respective bottom chord bars 22, 24 and the web against the inverted support channel 94 in preparation for sandwiching together the bottom chord bars and web. There are a plurality of tangs 96, one associated with each of the fastening shelf assemblies, all operated by a set of actuating devices, as exemplified by pneumatic cylinders 98. In the present instance the tangs 96 are each connected to a rotatable drive shaft 99 that is itself connected to a depending crank 100 suitably connected to the drive piston of one of the pneumatic cylinders 98. As can be best observed in FIG. 7, the rest or retracted position of tang 96 is shown in phantom, when the cylinder 98 is actuated and its drive piston extends, the crank 100 is pivoted upwardly and the tangs 96 swing down in a bell crank fashion into the apex of one of the web lower load points 19.

The next step after the tangs 96 are actuated to press down on the web lower load points 19 and lower chord bars 22, 24 on opposite faces of the web, is to actuate a set of sandwiching and holding forks 101. Each fastening assembly 90 includes one fork 101 located at an outboard end of the assembly. The forks are actuatable to press the lower chord bars 22, 24 and the lower load point of the web 19 against the backstop 95. To effect the latter, each of the forks 101 is provided with a crossarrn 102 coupled to the end of a drive rod 104. The latter extends centrally along the underside of inverted channel 94, being slidably supported by a bearing member, in the present instance, an angle 105 mounted crosswise of the channel 94. To slidably move rod 104, an end 106 of the latter is connected to an upright leg 107 of an angle 108. The angle 108 extends the length of the assembling portion of Station D and is slidably carried on respective pedestals 109 mounted at spaced intervals along the machine length on certain ones of upright beams 83. To transmit sliding movement to the angle 108 and thereby to each fork 101, in the present instance the angle 108 is connected by suitable means to pneumatic cylinders 110. The latter are mounted on pedestals 109 (see FIG. 8). To permit adjustment of the space between clamping fingers 101 and backstop 95, the end 106 of rod 104 is threaded and provided with a nut 111. Thus, different shapes and diameters of materials can be used for these component parts of the structural member.

Once the web and bottom chord bars have been clamped by forks 101, then the aligning tangs may be retracted or lifted, as viewed in FIG. 7, to facilitate the fastening of the bottom chord to the web. In one practical application of the present invention welding was used to accomplish the fastening or connecting. On completion of the fastening, the clamping forks 101 are actuated outwardly or extended, thereby releasing the assembled bottom chord and web.

The next step is to transfer the assembled bottom chord and web to the next station, Station G, where the top chord is brought into registry with the web, to which the bottom chord has already been fastened, and is tacked to one end of the web. A suitable elevating mechanism 112 is employed for the transfer step. As exemplarily shown an elevator beam 114 extending longitudinally of the machine is adapted to engage a plurality of spaded apart crossarms 113 (see FIG. 6), shown as having one end pivotably attached at 113a by a rod which is attached to the frame member 83 and each arm provided with rollers 115. The latter engage the bottom chord 12 when beam 114 is raised by actuation of a set of cylinders 116. The bottom chord is thereby lifted above the respective inverted channels 94 of each fastening assembly and permitted to be slid or rolled to the left as viewed in FIG. 5.

Flowing into Station G, along with the assembled web and bottom chord, are the top chord angles 25, 26. As can be observed from FIG. 3, the top chord angles 25, 26 are prepared at Stations E and F. At Station E suitable means are provided for cutting the top chord angles to correct length. One such means which has been advantageously employed is to flash weld ends of angles together so as to form a continuous string of angle, and then provide a cutting mechanism to cut the continuous string angle to the desired lengths.

The respective angles 25, 26 are of the same length, and are fed Station F for installation of plugs 36 and shoes 28, 29, 30, 31. Turning to FIG. 9, thereshown is a rack having a plurality of runners, one runner 118 being shown. The angles cut to correct length are stored on the runners, ready to be pulled into position for processing. One angle for each joist is provided with plugs or reinforcements 36. Each of the angles are provided with suitable mounting fittings adapted to engage load bearing members when the structural members are installed. In the present instance these are the shoes 28, 29, 30, 31.

First describing the procedure for installing the plugs, the angle, for example, angle 26, is placed on a first bank of rollers 119, one roller being shown. There are two additional banks of rollers 120, 121, the purpose of which is explained subsequently. As best shown in FIG. 10, the angle 26 is positioned along the front of the roller bank 1 19 against a retaining ledge 122. At spaced intervals, the ledge 122 is provided with struck out tabs 124. The latter are located at predetermined distance apart, for one exemplary size joist at 2 foot intervals, and shaped to carry plugs 36, gravity held against the angle 26. As will be appreciated from a subsequent explanation of how the top chord is connected with the web, the plugs must be located so as not to lie at the web top load points, but instead between the top load points. Accordingly, the angle 26 is brought into predetermined longitudinal registry with the ledge 122 so that the plugs can be simply laid into place, and they will be correctly located. Generally the plugs are installed in the midsection of the joist and at positions computed to be particularly stressed when the structural member is used.

To hold the angle in position pressed against the ledge 122 while the plugs are being fastened to the angle by suitable means, for example by welding, a plurality of bellcrank assemblies 125, one of which is shown, are provided. Assembly 125 includes a bellcrank 126 pivotably supported at 128 on an upright frame member 129. The head end of the bellcrank 126 is provided with a T-shaped member 130 adapted to swing. into position to engage the inside corner of angle 26. To actu-" ate the bellcrank, in the present instance a pneumatic cylinder 131 having its plunger 132 coupled to a connecting beam 134 is mounted on the lower end of bellcrank 126 so as to actuate all of the bellcranks simultaneously.

As can be appreciated, the banks of rollers 119, 120, 121 are supported on upright frame members 129 and crossmembers 135 at a level suitable for conducting the fastening of the plugs to the angles. The rollers 120 are positioned above a floor 136 so that the plugs can be stored between the spaced rollers in binlike fashion. In one practical operation plugs are made by chopping round bars of steel having a diameter approximately three-quarter inch into lengths approximately 1 56 inches.

After the plugs are mounted on the angle, the angle is turned counterclockwise as viewed in FIG. 10 so that the plug carrying side of the angle is riding on the rollers 120. The angle 26 is now ready for an operation to attach mountings at its respective ends. Since at the subsequent Station G where the top chord for each joist is made up, there is required one angle with plugs and one angle without plugs, angles without plugs are also transferred to have mountings installed. Accordingly, for each angle with plugs, one angle without plugs is removed from the runners 118 and placed on the bank of rollers 121 to serve as top chord angle 25.

The angles 25, 26 are transported to the right, as viewed in FIG. 9, onto a shoe welding platfonn 138. The latter can take various forms, in the present instance an adjustable stop 139 is provided at one end of a pair of respective long, narrow traylike bins 140, 141. Only one stop mechanism 139 is shown for bin 140, however, another stop mechanism can be provided at a desired position in bin 141. The stops are staggered so that shoes can be simultaneously attached at selected positions along the platform 138. As best shown in FIGS. 1 and 2, in the exemplary practice of the invention the shoes are short angle pieces that are fastened to one leg of the top chord angle in a manner to provide a flat, load transferring surface along the lower side of the top chord when installed as a part of the structural member.

After the shoes are attached to the respective ends of the top chord angles, they are transported along a bed of rollers 142 to Station G to be aligned and registered with the assembled web and bottom chord. To facilitate the fastening of the plugs 36 to the other angle, efiected at Station I as explained subsequently, the angle 25 without the plugs is fed on roller wheels 144 toward Station G so that it is on the bottom and the angle 26 is placed on top with the plugs 36 sandwiched between the angles. That positioning permits the plugs 36 to be welded to the angle 25 looking down upon the work.

It is another feature of the present invention that respective longitudinally extending parts of a structural member can be brought into predetermined registry and alignment, a wide range of widths and any practical length of structural member being accommodatable. Turning to FIG. 11, (Station G) there shown are the respective longitudinally extending parts of the structural member, the assembled intermediate member 11 and one side member 12, and the yet separate other side member 14. These are brought together in a generally horizontal movement or flow. For receiving the joist, now lying on its side or one face, and for aligning the connected web and bottom chord assembly with the top chord angles, a machine 145 is provided. The assembled web and bottom chord are horizontally fed on a rack of rollers 146, the latter providing support for a structural member fed into the machine 145. To bring the web and bottom chord into correct depth relationship with the top chord angles, first the angle 25 is longitudinally transported on guiding roller wheels 144 until a stop mechanism 147 is engaged. Spaced a predetermined distance from the roller wheels 144 is an upright roller 148. The latter is a part of a lower chord aligning assembly 149 (see FIG. 12) which includes a yokelike supporting frame 150 in which the roller 148 is journaled and a positioning bar 152 to select the desired location for the roller 148. The frame 150 is slidably supported on upright frame legs, one of which 151 is shown. The positioning bar 152 is transversely movable relative to an upright frame beam 154 and carries a plurality of notches 155 engageable with a cog 156 carried by the frame member 154. The frame 150 is mounted on a beam assembly 158, having a cross section resembling an inverted channel coextensive with a portion 159 of the bar 152. By lifting an end 160 of the bar, the latter can be slid to move the roller 148. The notches are positioned, in the present instance, at 2 inch intervals, to accommodate the standard depth sizes of joists. As can be appreciated it is a feature of the present invention that various depth sizes of structural members can be accommodated at Station 6 very easily by moving positioning bar 152. Also, the exemplary structure can be changed to accommodate other types of structural members without departing from the spirit of the invention.

Accordingly, once the roller 148 is positioned for the particular size of joist that is being fabricated at the time, the assembled web and bottom chord are moved into correct relationship in respect of the top chord angle 25 with the upper load points 20 of the joist overlying a leg of the angle. At that time the mating angle 26 for the top chord is slid into position to overlie the web top load points with the plugs 36 sandwiched between the respective angles and located, longitudinally between the load points.

The angle 27 is brought up against the stop mechanism 147. Describing the stop mechanism, the latter includes a pivotably mounted stop plug 161 carried on a pintle 162 and adapted to swing into position to engage a forward end of the respective angles 25, 26. The pintle 162 is mounted on a carriage 164 which includes a top plate 165, a bottom plate 166 and a crank operated threaded bolt 168. The carriage 164 is movable within a channel 169 which has a transverse top plate 170 with a slot 171. The end of bolt 168 is rotatably mounted in bottom plate 166 and threadably mounted in top plate 165. Accordingly, by turning the bolt 168 in one direction the top plate 165 is moved away from bottom plate 166, so that the carriage 164 can he slid in slot 171, and turning the bolt 168 in the opposite direction, the top plate 165 is drawn against the bottom plate 166 to anchor the stop mechanism.

For each length of joist the proper distance is computed between the first lower web load point, in the exemplary practice of the method located generally near roller 148, and the end of the top chord angle. In the present instance, the stop mechanism 147 is positioned by reference to a distance indicator represented by tape 172 provided along the front of channel 169. To adjust the stop mechanism 147 at the correct position the carriage 164 is moved so that it is at the correct position as shown on the tape 172 and the handcrankoperated bolt 168 is tightened down to hold the carriage in place. The foregoing shows the ease with which the present invention permits different size structural members to be brought into correct alignment and registry.

The upper chord angles and the assembled web and bottom chord are clamped together for the subsequent step of preliminarily connecting, in the present instance tack welding, the web to the top chord to maintain the structural member parts generally aligned and registered during final assembly. To efiect the clamping, a top chord clamp mechanism 174 and a bottom chord clamp mechanism 175 are provided, in the present instance adapted to engage angles. Describing the angle clamp mechanism 174, it includes a pivotally mounted plate 176 carried on a pin 178. An upper end 179 of plate 176 is movable relative to an anvil or stationary member, in the present instance the aforementioned channel 169, to provide a space for an angle leg to fit between the plate and channel. For swinging or pivoting the plate 176 to clamp the angle leg against the channel 169, a pair of depending legs 180 are provided at the opposite comers of the lower edge of plate 176, one being shown, and a pair of respective pneumatic cylinders 181 are carried thereon. A set of plungers 182, one plunger comprising a part of each of the pneumatic cylinders 181, are adapted to act against upright frame members 154 to swing respective depending legs 180 and the plate 176, about pivot 178. The effect of actuation of cylinders 181 is to swing the lower end or edge of plate 176 away from the upright beam, while the upper end 179 of the plate presses the angle against channel 169.

Describing exemplary apparatusfor gripping or clamping the bottom chord at Station G, a tang 184 is pivotally mounted on a pin 185 carried by channels 158. A lower end 186 of the tang 184 is pivotally connected to a plunger 188 of a pneumatic cylinder 189. The opposite end of the pneumatic cylinder 189 is pivotally mounted on a pin 190 carried by a downwardly extending arm 191 mounted on channels 158. The upper end of tang 184 is adapted to swing into the web panel to press against the bottom load point 19 of the joist. As can be seen in FIG. 12, actuation of the plunger 188 swings the tang 184 in a counter clockwise direction and presses the web and bottom chord against the roller 148.

FIG. 14 sets forth a control diagram for effectuating sequential operation of the clamps at Station G. As thereshown a control circuit 192 is selectively connected by a push bottom switch 194 to a suitable source of power 195, for example, 1 volts AC. First, the bottom chord tang is actuated by operating pushbutton PBl, which applies energization to relay R1 which mechanically actuates contacts CRla, CRlb. Actuation of contacts CRla effects a bypass of pushbutton FBI and maintains the relay R1 energized. Closing of contacts CRllb energizes a solenoid S1 which operates appropriate valving to effect operation of pneumatic cylinder 189. As explained, that results in tang 175 being pivoted to engage the bottom chord at the aforementioned first or end-adjacent load point.

Next, pushbutton PB2 is actuated to energize relay R2. The energization of the latter closes contacts CR2a, CR2b. Closing of contacts CR2a bypasses pushbutton contact PB2 and maintains relay R2 energized. The closing of contacts CR2b energizes solenoid S2 which provides pneumatic power for cylinders 181, the operation of which clamps the top chord angle.

As a result of the above-described clamping of the bottom chord-web and the top chord, the web and top chord are aligned and prepared to be connected. In the present instance, a suitable tack welding procedure is followed to weld the respective angles of the top chord to the web, for example, at end 79 (FIG. 11) of the web and at the top end of strut 34. Thus, a forward end of the structural member is connected together. The tacked together joist is moved while lying in a horizontal position over a feed platform 201 having a plurality of rollers 204 extending between respective longitudinally extending frame members 205, 206.

The feed platform 201 is adapted to direct the partially assembled structural member into the mouth or input of a final assembly machine. The final assembly machine is represented by Station H in FIG. 3 and is described in detail in my aforementioned copending application. At Station H one of the longitudinally extending side members of the structural member, in the exemplarily embodiment the top chord 14, is located in predetermined relationship to the intermediate member and other longitudinally extending side member of the structural member. The top chord, in the present instance angles 25, 26, is clamped together with the intermediate member, in the present instance with the respective angles disposed on opposite sides of the web top load points 20. Thereafter a suitable fastening procedure is conducted to connect the top chord angles with the web. The exemplarily practice of the invention uses an arc welding procedure.

The inventive final assembly process and apparatus includes as a feature, an operation for locating and clamping the top chord 14 in predetermined relationship to the web 11 and bottom chord 12 so as to permanently-impart to the completed structural member a desirable camber or bow. It is useful to have the latter in certain structural members which are subjected to transverse loading because the camber compensates for the yield in the structural member and results in maintaining the applied load a a substantially level status.

After the top chord 14 has been connected to the web 11 the fabrication of the joist is complete except for connection of the plugs 36 to the mating top chord angle and an inspection of the joist. To this end, there is provided at Station I a platform on which the structural member is carried and suitable means are provided for fastening the plug 36 to the angle 25. In the present instance, a manual operation is conducted of arc welding the plug to the angle. The inspection includes a visual or instrument check of the connections that have been made in fabricating the structural member and includes performance of supplementary work on the connections where the inspection indicates the necessity.

Accordingly, the foregoing description makes it clear that the present invention provides an improved system and apparatus for fabricating a structural member where several longitudinally extending parts are to be joined together, and where the dimensions of the finished structural member are to be maintained within close tolerances understood in the industry. It is further clear that the respective parts or components of the structural member can be handled in a continuous or flowing process eliminating extensive manual operations. Furthermore, it is clear that the method is versatile and permits of easy change to meet specifications for made-to-order structural members. The process and apparatus permits easy adjustment both for depth or width of the structural member as well as length of the structural member. in addition the process and apparatus permits the use of various materials which can be shaped, formed and connected using the concepts of the present invention as disclosed and claimed herein.

1 have described my invention in connection with one specific process and an exemplary apparatus useable in the practice of the process, it is to be understood that this is by way of illustration and not by way of limitation and the scope of my invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit.

I claim as my invention:

1. In a method for fabricating a structural member comprising the steps of shaping a longitudinally extending intermediate member so as to provide a first and a second set of peripherally aligned stress points; forming a first longitudinally extending side member of sufficient length to connect said first set of peripheral stress points; connecting the intermediate member with said first longitudinally extending side member along said first set of stress points; forming a second longitudinally extending side member of sufficient length to connect said second set of peripheral stress points; connecting the intermediate member with said second longitudinally extending side member at a predetermined one of said second set of stress points; locating said second longitudinally extend ing side member with respect to said first longitudinally extending side member and in predetermined relationship with said intermediate member, and connecting said second longitudinally extending side member to said intermediate member at said second set of stress points.

2. The method of claim 1 including a step of clamping sai located second longitudinally extending side member prior to its being connected with said intermediate member.

3. The method of claim 1 wherein said shaping step for said intermediate member includes forming opposite end portions of the latter so that two more stress points are provided in one of said respective first and second set of stress points and forming one of said longitudinally extending side members connected with said greater number of stress points longer than said other longitudinally extending side member.

4. The method of claim 1 wherein prior to said step of connecting said second longitudinally extending side member, are included the steps of locating one end of said member in respect of a predetermined reference point on said intermediate member, and clamping said longitudinally extending side member together with said intennediate member.

5. In a method for fabricating a joist, comprising the steps of forming a web into a generally zigzag shape of predetermined depth and length and having respective top and bottom stress points located along opposite side; forming a bottom chord having a predetermined length and adapted to connect said respective web bottom stress points; connecting said web with said bottom chord at said bottom stress points; forming a top chord having a predetermined length and adapted to connect said respective web top stress points; aligning said top chord with said web top stress points and in predetermined registry with said assembled web and bottom chord; clamping said top chord and said web together in aligned and registered relationship; fastening said top chord and said web sufiiciently to maintain substantial alignment and registry; locating said top chord in precise spaced relationship with respect to said bottom chord and in contact with said web top stress points, clamping said top chord and said web together, and; fastening said top chord and said web at said web top stress points.

6. The method of claim 4 wherein one of said longitudinally extending side members is adapted to form a part of a top chord and including prior to the step of aligning said one longitudinally extending side member with the associated stress points of said intermediate member, the additional step of reinforcing said top chord at predetermined positions along the length of said top chord.

7. The method of claim 5 and including the step of placing mountings at opposite ends of said top chord prior to said top chord aligning step.

8. In a method for fabricating a structural member, comprising the steps of shaping a longitudinally extending intermediate member so as to provide a first and a second set of peripherally aligned stress points; forming a first longitudinally extending side member of sufficient length to connect said first set of peripheral stress points; connecting the intermediate member with said first longitudinally extending side member along said first set of stress points; forming a second longitudinally extending side member of sufficient length to connect said second set of peripheral stress points; connecting the intermediate member with said second longitudinally extending side member at a predetermined one of said second set of stress points; locating said second longitudinally extending side member with respect to said first longitudinally extending side member and in predetermined relationship with said intermediate member; locating one end of said second longitudinally extending side member in respect of a predetermined reference point on said intermediate member; clamping said second longitudinally extending side member together with said intermediate member; connecting said second longitudinally extending side member to said intermediate member at said second set of stress points; inspecting the assembly of the side members and intermediate member; and providing additional fastening at selected points of contact therebetween.

9. The method of claim 3 and including a step for connecting predetermined struts to said web.

10. In a mechanism adapted to align and register first and second longitudinally extending parts of a structure member, the combination comprising a platform for receiving the first longitudinally extending part; a first means along one side of said platform for guiding the second longitudinally extending part into proximity with one side of the first longitudinally cxtending part; a second means along an opposite side of said platform engaging the opposite side of the first longitudinally extending part to guide the latter into aligned relationship with the second longitudinally extending part; a selectively operable clamp cooperating with said second guide means for gripping the first longitudinally extending part; means selectively positionable a predetermined distance beyond said clamp and associated with the first guide means in the path of movement of the second longitudinally extending part to facilitate positioning the end of the latter; and means associated with said first guide means for clamping together the proximate portions of the first and second longitudinally extending parts.

11. The mechanism of claim 10 and including in combination means for adjusting said second guide means laterally relative to said first guide means to accommodate different size structural members.

12. The mechanism of claim 10 and including in combination an indicating means for said stop to facilitate aligning registering different length structural members.

13. The combination of claim 10 where said first means is a set of roller wheels adapted to guide a joist top chord angle and said second means is an upright roller adapted to guide a longitudinally extending joist bpttc m c hord. 

1. In a method for fabricating a structural member comprising the steps of shaping a longitudinally extending intermediate member so as to provide a first and a second set of peripherally aligned stress points; forming a first longitudinally extending side member of sufficient length to connect said first set of peripheral stress points; connecting the intermediate member with said first longitudinally extending side member along said first set of stress points; forming a second longitudinally extending side member of sufficient length to connect said second set of peripheral stress points; connecting the intermediate member with said second longitudinally extending side member at a predetermined one of said second set of stress points; locating said second longitudinally extending side member with respect to said first longitudinally extending side member and in predetermined relationship with said intermediate member, and connecting said second longitudinally extending side member to said intermediate member at said second set of stress points.
 2. The method of claim 1 including a step of clamping said located second longitudinally extending side member prior to its being connected with said intermediate member.
 3. The method of claim 1 wherein said shaping step for said intermediate member includes forming opposite end portions of the latter so that two more stress points are provided in one of said respective first and second set of stress points and forming one of said longitudinally extending side members connected with said greater number of stress points longer than said other longitudinally extending side member.
 4. The method of claim 1 wherein prior to said step of connecting said second longitudinally extending side member, are included the steps of locating one end of said member in respect of a predetermined reference point on said intermediate member, and clamping said longitudinally extending side member together with said intermediate member.
 5. In a method for fabricating a joist, comprising the steps of forming a web into a generally zigzag shape of predetermined depth and length and having respective top and bottom stress points located along opposite side; forming a bottom chord having a predetermined length and adapted to connect said respective web bottom stress points; connecting said web with said bottom chord at said bottom stress points; forming a top chord having a predetermined length and adapted to connect said respective web top stress points; aligning said top chord wiTh said web top stress points and in predetermined registry with said assembled web and bottom chord; clamping said top chord and said web together in aligned and registered relationship; fastening said top chord and said web sufficiently to maintain substantial alignment and registry; locating said top chord in precise spaced relationship with respect to said bottom chord and in contact with said web top stress points, clamping said top chord and said web together, and; fastening said top chord and said web at said web top stress points.
 6. The method of claim 4 wherein one of said longitudinally extending side members is adapted to form a part of a top chord and including prior to the step of aligning said one longitudinally extending side member with the associated stress points of said intermediate member, the additional step of reinforcing said top chord at predetermined positions along the length of said top chord.
 7. The method of claim 5 and including the step of placing mountings at opposite ends of said top chord prior to said top chord aligning step.
 8. In a method for fabricating a structural member, comprising the steps of shaping a longitudinally extending intermediate member so as to provide a first and a second set of peripherally aligned stress points; forming a first longitudinally extending side member of sufficient length to connect said first set of peripheral stress points; connecting the intermediate member with said first longitudinally extending side member along said first set of stress points; forming a second longitudinally extending side member of sufficient length to connect said second set of peripheral stress points; connecting the intermediate member with said second longitudinally extending side member at a predetermined one of said second set of stress points; locating said second longitudinally extending side member with respect to said first longitudinally extending side member and in predetermined relationship with said intermediate member; locating one end of said second longitudinally extending side member in respect of a predetermined reference point on said intermediate member; clamping said second longitudinally extending side member together with said intermediate member; connecting said second longitudinally extending side member to said intermediate member at said second set of stress points; inspecting the assembly of the side members and intermediate member; and providing additional fastening at selected points of contact therebetween.
 9. The method of claim 3 and including a step for connecting predetermined struts to said web.
 10. In a mechanism adapted to align and register first and second longitudinally extending parts of a structural member, the combination comprising a platform for receiving the first longitudinally extending part; a first means along one side of said platform for guiding the second longitudinally extending part into proximity with one side of the first longitudinally extending part; a second means along an opposite side of said platform engaging the opposite side of the first longitudinally extending part to guide the latter into aligned relationship with the second longitudinally extending part; a selectively operable clamp cooperating with said second guide means for gripping the first longitudinally extending part; means selectively positionable a predetermined distance beyond said clamp and associated with the first guide means in the path of movement of the second longitudinally extending part to facilitate positioning the end of the latter; and means associated with said first guide means for clamping together the proximate portions of the first and second longitudinally extending parts.
 11. The mechanism of claim 10 and including in combination means for adjusting said second guide means laterally relative to said first guide means to accommodate different size structural members.
 12. The mechanism of claim 10 and including in combination an indicating means for said sTop to facilitate aligning and registering different length structural members.
 13. The combination of claim 10 where said first means is a set of roller wheels adapted to guide a joist top chord angle and said second means is an upright roller adapted to guide a longitudinally extending joist bottom chord. 